/* $Id: closure.c,v 1.9 2010/06/09 08:21:47 tom Exp $ */

#include "defs.h"

Value_t *itemset;
Value_t *itemsetend;
unsigned *ruleset;

static unsigned *first_derives;
static unsigned *EFF;

static void set_EFF(void) {
	unsigned *row;
	int symbol;
	short *sp;
	int rowsize;
	int i;
	int rule;

	rowsize = WORDSIZE(nvars);
	EFF = NEW2(nvars * rowsize, unsigned);

	row = EFF;
	for (i = start_symbol; i < nsyms; i++)
	{
		sp = derives[i];
		for (rule = *sp; rule > 0; rule = *++sp) {
			symbol = ritem[rrhs[rule]];
			if (ISVAR(symbol)) {
				symbol -= start_symbol;
				SETBIT(row, symbol);
			}
		}
		row += rowsize;
	}

	reflexive_transitive_closure(EFF, nvars);

#ifdef		DEBUG
	print_EFF();
#endif
}

void set_first_derives(void) {
	unsigned *rrow;
	unsigned *vrow;
	int j;
	unsigned k;
	unsigned cword = 0;
	short *rp;

	int rule;
	int i;
	int rulesetsize;
	int varsetsize;

	rulesetsize = WORDSIZE(nrules);
	varsetsize = WORDSIZE(nvars);
	first_derives = NEW2(nvars * rulesetsize, unsigned) - ntokens * rulesetsize;

	set_EFF();

	rrow = first_derives + ntokens * rulesetsize;
	for (i = start_symbol; i < nsyms; i++) {
		vrow = EFF + ((i - ntokens) * varsetsize);
		k = BITS_PER_WORD;
		for (j = start_symbol; j < nsyms; k++, j++) {
			if (k >= BITS_PER_WORD) {
				cword = *vrow++;
				k = 0;
			}

			if (cword & (unsigned)(1 << k)) {
				rp = derives[j];
				while ((rule = *rp++) >= 0) {
					SETBIT(rrow, rule);
				}
			}
		}

		rrow += rulesetsize;
	}

#ifdef		DEBUG
	print_first_derives();
#endif

	FREE(EFF);
}

void closure(short *nucleus, int n) {
	unsigned ruleno;
	unsigned word;
	unsigned i;
	Value_t *csp;
	unsigned *dsp;
	unsigned *rsp;
	int rulesetsize;

	Value_t *csend;
	unsigned *rsend;
	int symbol;
	Value_t itemno;

	rulesetsize = WORDSIZE(nrules);
	rsend = ruleset + rulesetsize;
	for (rsp = ruleset; rsp < rsend; rsp++)
		*rsp = 0;

	csend = nucleus + n;
	for (csp = nucleus; csp < csend; ++csp) {
		symbol = ritem[*csp];
		if (ISVAR(symbol)) {
			dsp = first_derives + symbol * rulesetsize;
			rsp = ruleset;
			while (rsp < rsend)
				*rsp++ |= *dsp++;
		}
	}

	ruleno = 0;
	itemsetend = itemset;
	csp = nucleus;
	for (rsp = ruleset; rsp < rsend; ++rsp) {
		word = *rsp;
		if (word) {
			for (i = 0; i < BITS_PER_WORD; ++i) {
				if (word & (unsigned)(1 << i)) {
					itemno = rrhs[ruleno + i];
					while (csp < csend && *csp < itemno)
						*itemsetend++ = *csp++;
					*itemsetend++ = itemno;
					while (csp < csend && *csp == itemno)
						++csp;
				}
			}
		}
		ruleno += BITS_PER_WORD;
	}

	while (csp < csend)
		*itemsetend++ = *csp++;

#ifdef		DEBUG
	print_closure(n);
#endif
}

void finalize_closure(void) {
	FREE(itemset);
	FREE(ruleset);
	FREE(first_derives + ntokens * WORDSIZE(nrules));
}

#ifdef DEBUG

void print_closure(int n) {
	short *isp;

	printf("\n\nn = %d\n\n", n);
	for (isp = itemset; isp < itemsetend; isp++)
		printf("   %d\n", *isp);
}

void print_EFF(void) {
	int i, j;
	unsigned *rowp;
	unsigned word;
	unsigned k;

	printf("\n\nEpsilon Free Firsts\n");

	for (i = start_symbol; i < nsyms; i++) {
		printf("\n%s", symbol_name[i]);
		rowp = EFF + ((i - start_symbol) * WORDSIZE(nvars));
		word = *rowp++;

		k = BITS_PER_WORD;
		for (j = 0; j < nvars; k++, j++) {
			if (k >= BITS_PER_WORD) {
				word = *rowp++;
				k = 0;
			}

			if (word & (1 << k))
				printf("  %s", symbol_name[start_symbol + j]);
		}
	}
}

void print_first_derives(void) {
	int i;
	int j;
	unsigned *rp;
	unsigned cword = 0;
	unsigned k;

	printf("\n\n\nFirst Derives\n");

	for (i = start_symbol; i < nsyms; i++) {
		printf("\n%s derives\n", symbol_name[i]);
		rp = first_derives + i * WORDSIZE(nrules);
		k = BITS_PER_WORD;
		for (j = 0; j <= nrules; k++, j++) {
			if (k >= BITS_PER_WORD) {
				cword = *rp++;
				k = 0;
			}

			if (cword & (1 << k))
				printf("   %d\n", j);
		}
	}

	fflush(stdout);
}

#endif
